This invention relates to a process and apparatus for cleaning and eliminating of oil field mud and waste pits, while recovering useful hydrocarbons and water.
During oil well drilling and production operations, a substantial quantity of contaminated water and other drilling and production fluids is dumped into unlined earthen pits and remains there for an indefinite period of time.
The use of such unlined pits was a preferable method of disposal for more than 1,400 oil fields found in the state of Louisiana alone since 1901.
This situation causes contamination of not only soil in the areas surrounding the oil well pits but also of underground water tables, since the contaminated water penetrates through the walls of the oil well pit creating environmental and ecological hazards.
A number of new regulations provide for the operation of waste pits. Some of them require that the pits be lined with plastic or clay to prevent leakage to contaminated fluids into adjacent areas. Other require that oil well pits be completely eliminated.
Various methods have been employed to fulfill these tasks. Some methods require that the contents of the waste pits are hauled off site and burned or recycled. Others require that the liquid be injected into the ground. The solids are then mixed with the soil or with fly ash. Other methods include burning the waste or moving it to lined areas with subsurface drainage. The levee around the pit is pushed in and the area is smoothed.
Since regulations about elimination of open oil waste pits become more rigorous every year, there clearly exists a need for a reliable system which would eliminate contents of the oil waste pit on site, thus substantially reducing the cost of disposal of oil field waste, including drilling mud and the salt water produced by the well. The cost of elimination of the oil waste pits can be further reduced if the contents of the waste pits are separated into liquids and solids and the liquids are treated to recover useful hydrocarbons and water.